Tool clamping device



United States Patent O The present invention relates to tool carriers and, more specifically, concerns a tool clamping device with steep cone connection. With la heretofore known clamping device of this type, the steep cone has diagrammatically oppositely located portions thereof provided with protrusions adapted at least indirectly to engage an inner groove of an element surrounding same, said groove being y designed to act as lead cam upon said protrusions in response 4to a relative rotation between cone and groove carrier.

It is an object of this invention to improve the above mentioned clamping device in such a way that the holding means for the cone will simultaneously chuck the same.

It is another object of this invention to provide an irnprovement of the type set forth in the preceding paragraph which is of simple and reliable construction Iand will assure that the cone be chucked concentrically.

It is a further object of this invention to provide a clamping device as set forth in the preceding paragraphs, which will also be employable with very slender boring tools.

These and other objects and advantages of the invention will appear more' clearly from the following specification in connection with the accompanying drawings, in which: p

FIG. l represents a longitudinal section through a clamping device according to the invention.

FIG. 2 is a cross section taken along the line 2--2 of FIG. 1.

FIG. 3 is a cross section similar to that of FIG. l through a modified clamping device according to the invention.

FIG. 4 is a section taken along the line 4 4 of FIG. 3.

FIG. 5 is a partial longitudinal section taken along the line 5-5 of FIG. 4.

The tool clamp-ing device or chuck according to the present invention is characterized in that protrusions are provided at the two ends of a longitudinal displaceable pin extending through the cone which protrusions have inclined surfaces adapted to be acted upon -by lead cams in response to a certain rotation whereby the cone is driven into the receiving part therefor.

Due to the longitudinal displaceability of the transverse pin carrying the protrusions of both sides, it will in contrast to heretofore known clamping devices of the type involved be assured that both protrusions will uniformly become effective so that a situation will be prevented in which due to differences in the tolerances one protrusion will be effective rst with the result that the cone will be unilaterally pressed into the cone receiving part. If provision is made that the inner grooves are provided on the inner surface of the cone receiving part and that one ank of said inner grooves in the form of a guide cam will directly act upon the protrusions in a bayonet joint manner, it will not be necessary to provide a guide cam in a screw collar ring surrounding the cone receiving part. So designed, the clamping device may also be used in connection with very slender boring tools.

Referring now to the drawings in detail and FIGS. 1 and 2 thereof in particular, the embodiment shown therein has one end of a tool spindle 11 provided with an inner ICC conical surface 11a and forms the receiving part for a steep cone 12a of a shank 12 of a tool holder.

vThe steep cone 12a has a transverse bor-e 12b through which extends a pin 13 which is slightly resiliently yieldable and longitudinally displaceable in said transverse bore. To this end, the pin 13 has its circumference provided With a depression 13a into which a ball 15 may be pressed by means of a spring 14. This spring 14 is mounted in a central bore 12e of steep cone 12a and has its upper end rest against a shoulder of a screw 16 threaded into the steep cone 12a. Screw 16 has a central pinlike extension 16a for limiting the movement of ball 15 to such an extent that pin 13 will not be able accidentally to leave the transverse bore 12b. For purposes of introducing the ends of pin 13 into the spindle 11 serving as receiving part, the spindle is furthermore provided with axially extending grooves 11b, said ends of pin 13 protruding beyond the outer surface of the steep cone 12a. The axially extending grooves 11b have a narrow passage 11c within the range of the protrusions of such a width that it will receive therebetween the ends of pin 13 which ends at this portion are provided with lateral flat parts 13b. In this Way, there will at any rate be assured a positive lengagement of the cone with the cone receiving part so that the cone will be positively rotated when the receiving part 11 turns.

Substantially at the extension of the inserted pin 13, the cone receiving part 11 is provided with transverse bores 11d, having balls 17 inserted therein. These balls simultaneously engage inner grooves 18a of a collar ring 18 which is loosely rotatable on the spindle 11 and secured by spring rin-g 19 against accidental withdrawal. The bottom 18h of grooves 18a is designed as lead cam for the balls in such a way that when ring 18 moves out of its FIG. 1 and 2 position, the balls will be pushed inwardly so that they will pass below the inclined surfaces 13o of the ends of pin 13 and in response to a further rotative movement of said ring 18 will lift pin 13 and thereby drive steep cone 12a into the receiving conical bore 11a. Due to the fact that pin 13 is longitudinally displaceable to a limited extent, it will be assured that no ball will become effective ahead of the other ball whereby a unilateral pressing of the cone could be effected.

Referring now to the embodiment of FIGS. 3 to 5, this embodiment likewise shows the shank `12 of a tool holder with the steep cone 12a having a transverse bore 12b. However, in this instance a differently formed transverse pin is inserted into said transverse bore 12b. However, also in this instance the transverse pin 23 is to a limited extent yieldably and longitudinally displaceably held in said transverse bore by means similar to those described in connection with the embodiment of FIGS. 1 and 2, namely by a ball 15, a spring 14, a screw 16 and an extension 16a of said screw.

The spindle 21 is also in this instance provided with axially extending grooves 2lb for the protruding ends of pin 23.

In this instance, the inner conical receiving surface 21a of spindle 21 is directly provided with an inner groove 21d. As will be evident from FIG. 4, the lower side flank of said inner groove 21d has at 21e an ascending inclined surface. It is with these inclined surfaces that the inclined surfaces 23e of the protruding ends 23a of transverse pin 23 cooperate in such a way that when a rotation of the steep cone 12a occurs relative to spindle 21, the said protrusions ascend on the inclined surfaces 21e thereby pressing shank 12a into the receiving cone 21a. Also in this instance the fact that pin 23 is longitudinally displaceable brings about a compensation in so far as neither one of the two groove sides can first and alone become effective -whereby a unic a lateral pressing of the steep cone into the receiving cone would be effected.

It is, of course, to be understood that the present invention is, by no means, limited to the particular constructions shown in the drawings but also comprises any modifications within the scope of the appended claims.

What we claim is:

1. In a tool clamping system: a rst member having a conical portion, a second member provided with a conical bore corresponding to said conical portion for receiving the latter, said conical portion being provided with a transverse bore, pin means axially displaceably mounted in said transverse bore and having its ends protrude beyond said transverse bore at diametrically opposite sides of' said conical portion, said protruding ends of said pin means being provided with inclined surfaces, and means surrounding at least a portion of said conical portion Within the range of said inclined surfaces for engaging the same in response to a certain rotation of said means relative to said pin means to thereby drive said iirst member into said second member.

2. An arrangement according to claim 1, in which said pin means comprises a depression, and which includes engaging means for engagement with said depression, an adjustable member mounted in said conical portion, and spring means interposed between said adjustable member and said engaging means for continuously urging said engaging means into said depression, said adjustable member having an extension forming an abutment for said engaging means and normally occupying a position to allow said engaging means to move against the thrust of said spring means by a distance insuicient to completely disengage said depression.

3. In a tool clamping system: a rst member having a conical portion, a second member provided with a conical bore corresponding to said conical portion for receiving the same, said conical portion being provided with a transverse bore, and pin means axially displaceably mounted in said transverse bore and having its ends provided with inclined surfaces and protruding therefrom at diametrically opposite sides of said conical portion, said second member having a portion surrounding said conical portion within the range of said inclined surfaces and being provided with a cam area for engagement with said inclined surfaces in response to a certain rotation of said rst and second members relative to each other to thereby cause said cam area to drive said first member into said second member.

4. In a tool clamping system: a rst member having a conical portion, a second member provided with a conical bore corresponding to said conical portion for receiving the same, said conical portion being provided with a transverse bore, pin means axially displaceably mounted in said transverse bore and having its ends provided with inclined surfaces and protruding therefrom at diametrically opposite sides of said conical portion, said second member having passage means provided within the range of said pin means, ring means mounted on said second the intervention of said pin means into said second member.

References Cited in the file of this patent UNITED STATES PATENTS Knott July 16, 1927 Currier Nov. 11, 1930 

1. IN A TOOL CLAMPING SYSTEM: A FIRST MEMBER HAVING A CONICAL PORTION, A SECOND MEMBER PROVIDED WITH A CONICAL BORE CORRESPONDING TO SAID CONICAL PORTION FOR RECEIVING THE LATTER, SAID CONICAL PORTION BEING PROVIDED WITH A TRANSVERSE BORE, PIN MEANS AXIALLY DISPLACEABLY MOUNTED IN SAID TRANSVERSE BORE AND HAVING ITS ENDS PROTRUDE BEYOND SAID TRANSVERSE BORE AT DIAMETRICALLY OPPOSITE SIDES OF SAID CONICAL PORTION, SAID PROTRUDING ENDS OF SAID PIN 